Real-time individual electronic enclosure cooling system

ABSTRACT

This discloses apparatuses for cooling individual server racks or electrical enclosures. These devices maintain target enclosure temperatures within plus or minus 1 or 2 degrees F. The devices employ industrial cooling using staged cooling towers to evaporatively reach temperatures below the wet bulb temperature of the ambient air. Methods for using such apparatuses are disclosed as well.

BACKGROUND

-   -   “Data center energy usage has risen dramatically over the past        decade and will continue to grow in-step with the processor        intensive applications that support business and day-to-day life        in the modern world. The growth of technology has driven the        data center into a new phase of expansion, and while data        centers themselves may vary over different industry segments,        there are common factors influencing all of them including a        need to do more with the same resources, or in some cases, even        less. To this end, much has been done to increase server        efficiency and IT space utilization, but the actual space and        cooling infrastructure supporting these intensified loads has        often not been properly addressed to keep pace with these        developments—an important oversight since cooling can represent        up to 42% of a data center's energy usage.”        Daniel Kennedy, Rittal White Paper 507: Understanding Data        Center Cooling Energy Usage & Reduction.

Available Cooling Systems

Over the years, many methods have been used to cool IT loads in the DataCenter environment. The master table below lists some methods commonlyused in the industry. These products are available from variousmanufacturers-some have been available for quite some time and othershave just recently been introduced. The table is not a complete list ofvendors, but is intended as a reference for some of the most commonlydeployed systems.

Table 1 illustrates energy usage by evaluating the energy required tooperate the system in kilowatts (kW) versus the cooling capacityprovided in tons of cooling/refrigeration (12,000 BTU/hr is equivalentto 1 ton of refrigeration)—a kW/ton rating.

TABLE 1 Commonality in the Availability Manufacturers Industry CRACCooled System 30+ Years Liebert, DataAire, Stultz Very Common CRAHCooled System 30+ Years Liebert, DataAire, Stultz Very Common CRACCooled System 5-10 years The above for Cooling Gaining WidespreadW/Containment units; containment from Acceptance Rittal, CPI, Polargy,APC, Knurr CRAH Cooled System 5-10 years The above for Cooling GainingWidespread W/Containment units; containment from Acceptance Rittal, CPI,Polargy, APC, Knurr Liquid Cooled Rack 8 years Rittal, APC, Knurr,Common Unoptimized Liebert, HP Liquid Cooled Racks 8 years Rittal, HP,Knurr Less Common Chilled Water Temperature Optimized Liquid CooledRacks 8 years Rittal, HP, Knurr Less Common Chilled Water TemperatureOptimized and Free Cooling Systems Liquid Cooled Racks 8 years Rittal,HP, Knurr Less Common Chilled Water Temperature Optimized andEvaporative Free Cooling Systems Active Liquid Cooled 5 years RittalLess Common Doors, Chilled Water Temperature Optimized and EvaporativeFree Cooling Systems Passive Liquid Cooled 8 years Rittal, IBM, VetteLess Common Doors Chilled Water Temperature Optimized and EvaporativeFree Cooling Systems Pumped Refrigerant 5 years Liebert Less CommonSystems Air Side Economizing 30+ Years Custom Engineered CommonSolutions with components from various providers Liquid Cooled Servers30+ Years Originally used in Rare mainframes, but proposed 100% heatremoval very rare, closest manufacturer would be SprayCool

Typical Data Center cooling is accomplished using standard HVACtechniques. That is, the whole building is cooled just as any otherbuilding is cooled using supply and return air ductwork, under-floor airdistribution space, air inlets, air outlets, etc. Primarily, the air isconditioned at a small number of locations and then moved throughductwork and/or via under-floor air distribution space to a desiredoutlet location. Once expelled from the outlet, the cooled air mixeswith room air. Eventually, the room air enters a server rack where itpicks up heat from the servers and the hot air is expelled back into theroom where it again mixes with room air. In some slightly moresophisticated systems, the server racks are arranged into aisles, whichdo a better job of segregating warmed air from cooled air. But in mostcases, heat is generated far from the location of the room temperaturecontrollers and far from where heat is removed. This distance causes abig thermal lag or inertia in the system and requires that some areas beover cooled to insure sufficient cooling building wide. This wastesenergy. The following table provides data about the capacity, operation;CAPital Expenditures (CAPEX) and OPerating cost Expenditures (OPEX) oftypical Data Centers where even the oversized cooling systems are unableto provide the required cooling to the all IT Room server rackenclosures.

Data Center LOST capacity is the inability to convert the intendeddesign loading capacity into operational reality, or in other words,resources are not fully utilized. Changes to the Data Center capacityroadmap, i.e. increased Rack load densities, which fail to conform toinitial design and design assumptions results in lost capacity. DataCenter capacity is LOST when changes from the original design causesspace, power, COOLING, or network to become unavailable to the ITequipment. For example, if Rack densities increase from 4 KW per Rack to8 KW per Rack, the IT load in the average enterprise Data Center isincreased from IX KW to 2×KW, but the COOLING system was initiallydesign for IX KW plus, in some cases, 50% accounting for unexpectedadditional COOLING requirements or 1.5×KW. At an increased density to2×KW per Rack, the Data Center will have to decommission 25% of itsRacks reducing its Data Center Capacity by 25% due to lack of COOLINGresources. Analysis shows an Annual Cost of Deployed Capital of $8,308per KW related to Data Center CAPEX and OPEX resulting in substantialcosts to the Data Center for loosing capacity due to lack of COOLING.

TABLE 2 Lost Capacity and its Capital Cost to a Data Center Based onFuture Facilities White Paper “The Elephant in the Room is LostCapacity” and the Uptime Institute Analysis of1.3 MW Data Center MWs  1.3 KWs 1300 Annualized CAPEX $6,300,000 Annualized OPEX $3,100,000Load Dependent OPEX $1,400,000 Total Annual Capital Deployed $10,800,000Total Annual Capital Deployed per KW $8,308 Lost Capacity - 20% for 1year and for $2,160,000 $10,800,000 5 years Lost Capacity - 30% for 1year and for $3,240,000 $16,200,000 5 years Lost Capacity - 40% for 1year and for $4,320,000 $21,600,000 5 years

What is needed is a system of cooling server racks or electronicsenclosures that more closely places cooling means near the heat load ofthe server and which is capable to provide real time cooling for anindividual server rack or electronics enclosure based on its loaddemand.

SUMMARY

Invention embodiments comprise a system comprising a multistageevaporative cooling system and an individual server enclosure coolingsystem. In various embodiments, the ISECS comprises a housing, a coolingcoil unit including a cooling coil mounted in the housing wherein thecooling coil is adapted to circulate a volume of cold water; a fan rackincluding at least one fan wherein the fan rack is located within orservices the housing; and a computer-based command-and-control system insignal communication with one or more sensors configured to sense acooling parameter wherein the individual server enclosure cooling systemis adapted to connect to or sit within a server rack or electronicsenclosure and wherein the individual server enclosure cooling system isin fluid communication with a multistage evaporative cooler.

In some embodiments the fan rack and the cooling coil unit sit withinthe housing at an air inlet to the server rack enclosure; the fan rackand the cooling coil unit sit within the housing at an air outlet fromthe server rack enclosure; the fan rack sits at an air outlet from theserver rack enclosure and the cooling coil units sits at an air inlet tothe server rack enclosure; or the fan rack sits at an air inlet to theserver rack enclosure and the cooling coil unit sits at an air outletfrom the server rack enclosure. Some embodiments use one, two, three,four, or more fans. Similarly, some embodiments use one, two, three,four, or more cooling coils.

Various embodiments draws electrical power at a rate of less than 0.93,0.9, 0.85, 0.82, 0.80, 0.78, 0.75, 0.73, 0.70, 0.69, 0.65, or 0.60kilowatts per ton of cooling.

In some embodiments, the system uses a computer-basedcommand-and-control system that monitors a cooling parameter. Someembodiments monitor the cooling parameter and run algorithms thatfacilitate drawing electrical power at a rate of less than 0.93, 0.9,0.85, 0.82, 0.80, 0.78, 0.75, 0.73, 0.70, 0.69, 0.65, or 0.60 kilowattsper ton of cooling. In some of these embodiments, the rate of electricalpower use is less than 0.60 kilowatts per ton of cooling underappropriate ambient and operating conditions. Sometimes monitoring acooling parameter encompasses evaluating the instantaneous value, atime-differentiated value, or a time-integrated value of the coolingparameter. In these or in these or other embodiments, the coolingparameter is at least one of air and water temperature; air and waterflows, differential air and water pressures, air humidity; electricpower consumption (loads) of racks, servers, power distribution units,uninterruptable power supplies, lighting, transformers and switchgear,pumps, fans, motors or combinations of these. In these or otherembodiments, the cooling parameters are measured throughout the systemsuch as measured through the individual server enclosure cooling system,in the individual server enclosure cooling system, or at some pointwithin the server rack enclosure or within some other part of thebuilding.

In some embodiments, the computer-based command-and-control systemadjusts at least one cooling control that manipulates a controlparameter. In these or other embodiments, a control parameter is any oneor any combination of fan speed for one or more fans; cooling fluid pumpspeed for one or more cooling coils; cooling fluid flow rate for one ormore cooling coils; cooling fluid temperature for one or more coolingcoils; or cooling air flow rate. Invention computer-basedcommand-and-control system may monitor one or more cooling parameters oradjusts one or more cooling controls such that the average temperatureof air moving through the server rack enclosure remains within 5, 4, 3,2, 1, 0.75, or 0.5 degrees of a set point temperature.

In some system embodiments, the cooling coil unit sits near the airoutlet of the server rack enclosure and comprises at least two coolingcoils and wherein the fan rack sits disposed cooling coil unit, whereinthe cooling coil unit and the fan rack are disposed within the housing;and wherein the individual server enclosure cooling system sits under afloor supporting the server rack enclosure or sits within the serverrack enclosure.

In some embodiments, an invention system comprises a multistageevaporative cooling system and an individual server enclosure coolingsystem adapted to connect to a server rack enclosure or located within aserver rack enclosure, wherein the individual server enclosure coolingsystem comprises a housing; a cooling coil unit including a cooling coilmounted in the housing wherein the cooling coil is adapted to circulatea volume of cold water; a fan rack including at least one fan whereinthe fan rack is located within or services the housing; and acomputer-based command-and-control system in signal communication withone or more sensors configured to sense a cooling parameter and thatmonitors at least one cooling parameter by evaluating an instantaneousvalue, a time-differentiated value, or a time-integrated value of thecooling parameter wherein the cooling parameter is at least one of airand water temperature; air and water flow; differential air and waterpressures; air humidity; or electric power consumption of racks,servers, power distribution units, uninterruptable power supplies,lighting, transformers, switchgear, pumps, fans, or motors and thecooling parameter is measured through the individual server enclosurecooling system, in the individual server enclosure cooling system, or atsome point within the server rack enclosure or within some other part ofthe building and wherein the computer-based command-and-control systemis capable of adjusting at least one cooling control that manipulates acontrol parameter comprising fan speed for one or more fans; coolingfluid pump speed for one or more cooling coils; cooling fluid flow ratefor one or more cooling coils; cooling fluid temperature for one or morecooling coils; or cooling air flow rate such that the averagetemperature of air moving through the server rack remains within 5, 4,3, 2, 1, 0.75, or 0.5 degrees of a set point temperature and wherein thefan rack and the cooling coil unit sit within the housing at an airinlet to the server rack enclosure; the fan rack and the cooling coilunit sit within the housing at an air outlet from the server rackenclosure; the fan rack sits at an air outlet from the server rackenclosure and the cooling coil units sits at an air inlet to the serverrack enclosure; or the fan rack sits at an air inlet to the server rackenclosure and the cooling coil unit sits at an air outlet from theserver rack enclosure and wherein the system draws electrical power at arate of less than 0.93, 0.9, 0.85, 0.82, 0.80, 0.78, 0.75, 0.73, 0.70,0.69, 0.65, or 0.60 kilowatts per ton of cooling. In some of theseembodiments, the rate of electrical power use is less than 0.60kilowatts per ton of cooling under appropriate ambient and operatingconditions.

FIGURES

FIG. 1 depicts a variation of an ISECS with an under-floor outlet.

FIG. 2 depicts another variation of an ISECS with an under-floor outletand two fans.

FIG. 3 depicts another variation of an ISECS with an under-floor outletand a rack-mounted fan.

FIG. 4 depicts another variation of an ISECS with an under-floor outletand dual rack-mounted fans.

FIG. 5 depicts another variation of an ISECS with an overhead outlet andan overhead fan.

FIG. 6 depicts another variation of an ISECS with an overhead outlet anda rack-mounted fan.

FIG. 7 depicts another variation of an ISECS with an overhead outlet anddual rack-mounted fans.

FIG. 8 depicts another variation of an ISECS mounted within a serverrack enclosure.

FIG. 9 depicts another variation of an ISECS mounted within a serverrack enclosure.

FIG. 10 depicts a cooling tower useful in cooling system embodiments.

FIG. 11 depicts another useful cooling tower further comprising anair-to-water heat exchanger or an air pre-cooling heat exchanger.

FIG. 12 depicts another useful cooling tower further comprising anenergy recovery system.

FIG. 13 depicts a cooling system embodiment.

FIG. 14 depicts another cooling system embodiment.

FIG. 15 depicts another cooling system embodiment.

FIG. 16 depicts a makeup air-handling unit.

FIG. 17 depicts an energy recovery system.

DETAILED DESCRIPTION

The following description of several embodiments describes non-limitingexamples that further illustrate the invention. No titles of sectionscontained herein, including those appearing above, are limitations onthe invention, but rather they are provided to structure theillustrative description of the invention that is provided by thespecification.

Unless defined otherwise, all technical and scientific terms used inthis document have the same meanings that one skilled in the art towhich the disclosed invention pertains would ascribe to them. Thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly indicates otherwise. Thus, for example, reference to“fluid” refers to one or more fluids, such as two or more fluids, threeor more fluids, etc. Any mention of an element includes that element'sequivalents as known to those skilled in the art.

Any methods and materials similar or equivalent to those described inthis document can be used in the practice or testing of the presentinvention. This disclosure incorporates by reference all publicationsmentioned in this disclosure and all of the information disclosed in thepublications.

This disclosure discusses publications only to facilitate describing thecurrent invention. Their inclusion in this document is not an admissionthat they are effective prior art to this invention, nor does itindicate that their dates of publication or effectiveness are as printedon the document.

The features, aspects, and advantages of the invention will become moreapparent from the following detailed description, appended claims, andaccompanying drawings.

Individual Server Enclosure Cooling System (ISECS)

In various embodiments, an invention individual server enclosure coolingsystem or a rack cooling system or electronics enclosure cooling system(collectively ISECS) uses a process cooling model to cool the equipmentinside of the rack or enclosure with real time monitoring and controlover the cooling needs of the IT and other Data Center supportequipment. In some embodiments, the cooling needs of a rack orelectronics enclosure range from 500 watts to ±50 kW, 1 kW to ±40 kW, or3 kW to ±35 kW. In some embodiments, an invention ISECS connects with areal time monitoring and control system, as described below. In someembodiments, an invention ISECS connects to a Multistage EvaporativeCooling System (MECS), as described below. In some embodiments, aninvention ISECS connects to a Multistage Evaporative Cooling System anda real time monitoring and control system. In some inventionembodiments, when connected to the MECS, the invention ISECS receivescold water at temperatures of 61±4° F., 61±5° F., 61±10° F., 61±15° F.,or 61±20° F.

This invention among other things applies semiconductor clean roomprocess cooling methods to Data Center or mission critical environmentsproviding real-time, load-based process cooling at the server rack orelectronics enclosure and eliminating hot and cold aisles by combiningthe Multistage Evaporative Cooling System (MECS—the cold watergenerating source), ISECS (ISECS), and Real Time Monitoring and ControlSystem (RTMCS).

Invention embodiments comprise cooling systems that are coupled with theserver rack or electronics enclosure containing the heat load. In someembodiments, ISECS attaches to server racks or electronics enclosures.ISECS or a local cooling system comprises a housing within which sits acooling coil or multiple cooling coils and a fan or multiple fans. Thehousing may additionally comprise air filters, dampers, condensate pan,condensate removal means, etc. ISECS also contains sensors andcontrollers attached to control system that enable the control system tosupply cooling capacity matched to the real-time needs of an individualserver rack or electronics enclosure.

FIG. 1, FIG. 2, FIG. 3, and FIG. 4 depict invention ISECS 1010 forplacement beneath a raised floor of one or more server rack enclosures1015 or electronics enclosures 1015. (Sometimes throughout this documentserver racks and electronics enclosures are referred to collectively asserver rack enclosure(s).) Alternatively, ISECS 1010 may sit in a crawlspace or basement beneath server rack enclosure 1015. ISECS 1010comprises hot air inlets 1076 into housing 1075 through hot air ductelbow 1077. One or more fan racks 1024 and one or more cooling coilunits 1027 are disposed within housing 1075. Fan rack 1024 comprises oneor more fans 1020. Cooling coil unit 1027 comprises one or more finalcooling coils 1025, and optionally one or more pre-cooling coils 1070are disposed within housing 1075. In some embodiments, at least onepre-cooling coil 1070 is disposed upstream of final cooling coil 1025within cooling coil unit 1027. FIG. 1 shows fan rack 1024 locateddownstream of cooling coil unit 1027, but other embodiments exist inwhich fan rack 1024 is located anywhere along the air path throughhousing 1075. Thus, some embodiments locate fan rack 1024 withoutrespect to the location of cooling coil unit 1027, final cooling coil1025, or pre-cooling coil 1070.

Hot air inlet 1076 into ISECS 1010 may attach to a standard server rackenclosure 1015 though hot air duct elbow 1077. ISECS 1010 in theembodiment depicted in FIG. 1, FIG. 2, FIG. 3, and FIG. 4 vents to theregion below the raised floor. Cool air exits ISECS 1010 into the regionunderneath the raised floor and in some embodiments air returns to theserver room through cold air discharge grill 1017 located within theaisle way between rows of server rack enclosures 1015. Some embodimentsemploy a condensate pan 1211 that captures water that condenses on thepre-cooling coil 1070 or the final cooling coil 1025, or both.

FIG. 2 depicts an invention embodiment substantially like that ofFIG. 1. The difference in this embodiment from that of the FIG. 1embodiment is that FIG. 2 depicts fan rack 1024 comprising two fans1020.

FIG. 3 depicts an invention embodiment substantially like that ofFIG. 1. The difference in this embodiment from that of the FIG. 1embodiment is that fan rack 1024 is located in server rack enclosure1015.

FIG. 4 depicts fan rack 1024 located similarly to FIG. 3, except fanrack 1024 comprises two fans 1020.

FIG. 5 depicts ISECS 1010 similar to the embodiments of this inventiondiscussed above, but in which ISECS 1010 is adapted to mount to the topof server rack enclosure 1015. In this embodiment, ISECS 1010 compriseshousing 1075 connected to the top of server rack enclosure 1015. Housing1075 contains, in order, an insulated hot air duct 1077 (in someembodiments an elbow), air filter 1026; followed by cooling coil unit1027, comprising precooling coil 1070 and final cooling coil 1025; fanrack 1024, comprising at least one fan 1020; and automatic air damper1201 and a louver door 1202 that provides access to fan rack 1024. Insome embodiments similar to FIG. 5, louver door 1202 comprises safetyfeatures that prevent fan 1020 from operating when louver door 1202 isopen. In these or other embodiments, an air duct 1074 (in someembodiments, an elbow) sits at the end of housing 1075 providing ductwork for air to exit ISECS 1010 from.

FIG. 6 depicts a cooling system embodiment that is similar to theembodiment shown in FIG. 5. FIG. 6 shows ISECS 1010 in which fan rack1024 sits at the outlet to server rack enclosure 1015.

FIG. 7 depicts a cooling system embodiment similar to that of FIG. 6 butin which fan rack 1024 comprises two or more fans 1020.

FIG. 8 depicts a cooling system embodiment in which ISECS 1010 is housedwithin server rack enclosure 1015. In this specific embodiment, ISECS1010 sits beneath the servers of server rack enclosure 1015. In otherembodiments, ISECS 1010 sits above the servers. This embodiment of ISECS1010 comprises air filter 1026; followed by cooling coil unit 1027,comprising pre-cooling coil 1070 and final cooling coil 1025; fan rack1024, comprising at least one fan 1020; and louver door 1202.

In some embodiments, housing 1075 is constructed of standard HVAC sheetmetal using standard HVAC construction methods. But in otherembodiments, housing 1075 is constructed using different methods ormaterials as is known to those of ordinary skill in the art.

In some embodiments, fan 1020 sits after a final cooling coil 1025 orpre-cooling coil 1070. In these or other embodiments, two, three, ormore fans compose fan rack 1024, which sits within housing 1075 of ISECS1010. In some embodiments, each fan 1020 has the same air-handlingcapacity as the others. In some embodiments, fans 1020 have differentair-handling capacities. Moreover, separate fans 1020 may servicepre-cooling coils 1070 and final cooling coils 1025, in someembodiments. Some of these embodiments divide the air path into two ormore paths. To prevent air back flow into ISECS 1010, some inventionISECS 1010 comprise one or more automatic air dampers 1201.

Similarly, in some embodiments ISECS may comprise two or more coolingcoils. Some embodiments comprise two or more cooling coils. Someembodiments comprise coils with substantially the same capacity and someembodiments comprise coils with differing capacities.

Final cooling coil 1025 attaches to a final cooling coil cold-waterinlet pipe 1040. As shown in FIG. 1 through FIG. 7, a final coolingwater flow control valve 1035 also attaches to final cooling coilcold-water inlet pipe 1040, as well. Final cooling coil 1025 alsoconnects to final cooling coil water outlet pipe 1045. ISECS 1010serving dedicated individual server rack enclosures 1015 connect tosecondary cooling loops fed by a MECS or by traditional water chillersthat provide cold water to one or more ISECS 1010. One pump providescold water to the pre-cooling coils 1070 of one or more ISECS 1010,while another one provides cold water to the final cooling coils 1025 ofat least one ISECS 1010. Together with various sensors, controllers, andcommand-and-control hardware or software, final cooling water flowcontrol valve 1035 allows control over cold-water flow through finalcooling coil 1025. Together with various sensors, controllers, andcommand-and-control hardware and/or software, precooling coil water flowcontrol valve 1060 allows control over cold-water flow throughprecooling coil 1070 to meet the cooling demand in real time. Coolingwater enters pre-cooling coil 1070 through pre-cooling coil cold watersupply pipe and leaves through pre-cooling coil water outlet pipe 1050.

The hot air inlet 1076 to ISECS 1010 may attach to a standard serverrack enclosure 1015 through hot air duct elbow 1077. The air exitsthrough a standard, perforated, cold air discharge grill 1017 supplyingcooled air back into the IT Room in the embodiment depicted in FIG.1-FIG. 5, for example.

In some embodiments the transition from the bottom of server rackenclosure 1015 into housing 1075 up to at least a final cooling coil1025 is thermally insulated to keep heat from the server from escapinginto the region beneath the raised floor or in the basement or crawlspace beneath server rack enclosure 1015. In some embodiments, athermally insulated hot air duct elbow 1077 extends from the housing1075 up into server rack enclosure 1015 to help direct hot air from theservers or other equipment into ISECS 1010.

Fans suitable for use in ISECS 1010 include any type of fan useful inthe HVAC arts. Some embodiments use variable speed fans in one or morepositions within ISECS 1010. The fans can be powered by any type ofmotor used in HVAC arts such as hydraulic, pneumatic, or later developedmotors adapted for use in that industry. Some invention fans are poweredwith energy-efficient motors. Invention fans can be fixed or variablespeed. For purposes of this invention, “fan” encompasses any devicedesigned to move air, such as air within an HVAC system. In addition toother air-moving devices, “fan” includes fans, blowers, etc.

Cooling coils useful in invention embodiments include any type ofair-to-water heat exchanger useful in the HVAC arts. The coils aresupplied with cold water using a system that comprises a water coolingsystem, comprising at least one shutoff valve. In some embodiments, theshutoff valve is combined with variable flow control. The water coolingsystem can be any cooling system as used in HVAC arts or other artsencompassing chilled water. Variable flow, shutoff valves can beremotely controlled in some embodiments. In some embodiments, at leastsome cooling load is serviced by a MECS as described below. In someembodiments greater than 25 percent, 50 percent, 75 percent, or 99percent of the cooling is supplied by a MECS, as described below.

Real Time Monitoring and Control System

Command-and-control systems, units, or devices such as a real time DataCenter cooling systems employing real time monitoring and controlsystems comprise programmable logic controllers (PLC), fieldprogrammable gate arrays, or programmable controllers that are or thatfunction as digital computers. In some invention embodiments, thedigital computer is configured for use in the automation ofelectromechanical processes. In addition to programmable controllers oralternatively to programmable controllers, some command-and-controldevices comprise computer-, microprocessor-, microcontroller-,programmable-logic-device-, or analog-based control systems. Generally,these are all referred to as computers or as computer-based.

A digital computer configured for use in the automation ofelectromechanical processes comprises at least one sensor. These orother embodiments comprise at least one controller. One or more sensorsmonitor a cooling parameter. A cooling parameter is any of thefollowing: air and water temperature; air and water flows, differentialair and water pressures, air humidity; electric power consumption(loads) of racks, servers, power distribution units, uninterruptablepower supplies, lighting, transformers and switchgear, pumps, fans,motors or combinations of these. The controllers control at least one ofair and water flow in real time to automatically adjusts watertemperature and flow, air temperature and flow, and motor and fan speedsto meet the immediate electric power consumption (loads) of eachindividual server rack enclosure or the immediate cooling needs of thespace or both.

Real Time Data Center Cooling System

Real Time Data Center Cooling Systems employing MECS generate cold waterto cool individual server rack enclosures for a Data Center have capitalexpenditure first costs and startup costs within about ±50% of the costsof traditional mechanical refrigeration systems. In some embodiments,the overall system uses no HVAC-type refrigeration compressors and nohalogenated refrigerant chemicals, such as freons.

Operation

For embodiments similar to those of FIG. 1, FIG. 2, FIG. 5, and FIG. 7,in which cooling fan 1020 sits downstream of final cooling coil 1025and/or pre-cooling coil 1070, the operation is as follows. In theoperation of local cooling systems ISECS 1010, one or more fans 1020composing fan rack 1024 move hot air from server rack enclosure 1015across one or more final cooling coil 1025 and/or pre-cooling coil 1070,dropping the temperature of the hot air to a target exhaust temperaturebefore returning the cooled air to the room. This air movementfacilitates room air to enter server rack enclosure 1015. Once insideserver rack enclosure 1015, the entering room air stream cools theservers in server rack enclosure 1015 becoming hot in the process.Operation of cooling system fans 1020 causes air to move through serverrack enclosure 1015 and pick up heat from the servers. This aircontinues through housing 1075 where it passes over final cooling coil1025 and/or pre-cooling coil 1070 and transfers heat to the coolingwater. Finally, the cooled air passes fan 1020 and exits cooling unithousing 1075, returning to the room. The air coming out of ISECS 1010pressures the total underfloor space. The pressure causes the return airto be discharged through perforated tiles or cold air discharge grill1017.

In embodiments similar to FIG. 3, FIG. 4, and FIG. 6, since fan 1020pushes air through ISECS 1010, cooled air exits cooling unit housing1075 without passing fan 1020.

Any number of sensors as described above sense the power usage of theservers, power supplies, or other equipment within server rack enclosure1015, as discussed above. Sensors can also monitor air temperature andother conditions and parameters of the air. The command-and-controlsystem receives signals from one or more sensors and applies specialalgorithms to adjust one or more controllers so that an appropriateamount of cooling is accomplished. The amount of cooling is commensuratewith the cooling needs of the individual server rack enclosures 1015.

In some embodiments, the command-and-control system adjusts airflowthrough ISECS 1010 to adjust the amount of cooling. Airflow adjustmentscome from adjusting fan 1020 speed. In these or other embodiments, thecommand-and-control system adjusts the flow rate of cooling waterthrough final cooling coil 1025 and/or pre-cooling coil 1070 to adjustthe amount of cooling. Cooling water flow rate can be adjusted byadjusting water flow control valves, either 1035 and/or 1060, for eachindividual local cooling system and adjusting speeds of the main pumpsserving the secondary cooling water loops as well as in some embodimentsadjusting accordingly cooling capacity of cooling water loops. In someembodiments, environmental air conditioning for the data center isprovided by cooling coils serviced with cold water from a MECS, asdefined in this document.

In some embodiments, ISECS use less than 0.93, 0.9, 0.85, 0.82, 0.80,0.78, 0.75, 0.73, 0.70, 0.69, or 0.69 kilowatts of energy to provide oneton of cooling.

TABLE 3 Real Time Data Center Cooling System Energy and GHG (CarbonFootprint) Savings Compar- ing Various Data Center Cooling System EnergyUsage in KW/Ton. KW/Ton data from Rittal White Paper 507: UnderstandingData Center Cooling Energy Usage & Reduction Methods by Daniel Kennedy.White Paper 507 uses the annual average temperature of six major UScities, whereas, the Real Time Data Center Cooling System uses a WorstCase Scenario - Phoenix Sum- mer Design Conditions for Average DataCenter Liquid Condenser Evap- Chilled Refrig- Pumped Cooled TotalFan/Cool- Com- orator Water erant Refrig Humid- Svr Server KW/ ing Towerpressor Fan Pump Pump Fan ification Pump Fans Ton| CRAC Cooled 0.24 1.290.51 0.58 0.26 2.88 System CRAH Cooled 0.16 1.12 0.51 0.10 0.58 0.262.73 Systems - Chilled Water Based CRAC Cooled System 0.21 1.25 0.450.50 0.26 2.67 w Containment CRAH Cooled System 0.15 1.08 0.45 0.10 0.500.26 2.54 w Containment Liquid Cooled 0.15 1.08 0.28 0.10 0.50 0.26 2.37Racks Unoptimized Liquid Cooled 0.13 0.96 0.28 0.09 0.26 1.72 RacksChilled Water Temperatures Optimized Liquid Cooled 0.13 0.63 0.28 0.090.26 1.39 Racks Chilled Water Temperatures Optimized and Free CoolingSystems Liquid Cooled 0.22 0.36 0.28 0.09 0.26 1.21 Racks Chilled WaterTemperatures Active Liquid 0.22 0.36 0.24 0.09 0.26 1.17 Cooled Doors,Chilled Water Passive Liquid 0.22 0.36 0.09 0.26 0.93 Cooled DoorsChilled Water Pumped Refrigerant 0.16 1.12 0.10 0.04 0.06 0.26 1.74Systems Air Side 0.05 0.37 0.51 0.03 0.19 0.26 1.41 Economizing NaturalCycle Energy Inc.

Note 1: Rittal Corporation White Paper Data—The impact of these energysavings is dependent on the installation location because of thevariances in ambient outdoor temperatures in different parts of theworld. The average annual hourly energy usage analysis figures for sixmajor cities (New York, Chicago, San Francisco, Phoenix, Miami, andAtlanta) were used in developing this analysis and KW/Ton calculations.Overall, these cities average approximately 2,856 hours of free cooling,or 33% of the year. The summer design cooling criteria for each city wasnot used, only the annual averages.

Note 2: Natural Cycle Energy, Inc. data and analysis for determiningenergy usage of the Real Time Data Center Cooling System (RTDCCS), whichincorporates the Multistage Evaporative Cooling System (MECS) and theIndividual Server Enclosure Cooling System (ISECS), is based on ASHRAEsummer design conditions for cooling applications in Phoenix Ariz. at0.4% Occurrence i.e. 110.2° F. DB and 70° F. WB. Therefore, it can beassumed the KW/Ton for the RTDCCS is higher than it would be if usingthe same six city averages used in the Rittal White.

TABLE 4 KW per Ton Analysis Comparing Various Data Center CoolingMethods vs. Real Time Data Center Cooling System Multistage EvaporativeCooling System (MECS) Total kW/Ton Cooling towers all with fans, pumps,etc. 0.29 See Note 2, above. Individual Server Enclosure Cooling System(ISECS) Rack Fan Coil Unit 0.14 See Note 2, above. Server Fans 0.26Total Real Time Data Center KW per Ton Cooling System 0.69

TABLE 5 Natural Cycle Energy, Inc. Energy Usage Comparison ofTraditional Data Center Cooling Systems to the Natural Cycle Energy,Inc. RTDCCS Traditional Mechanical Cooling KW/Ton % Energy KW/Ton RTDCCSSavings Savings CRAC Cooled 2.88 0.69 2.19 76.0% System CRAH Cooled 2.730.69 2.04 74.7% Systems - Chilled Water Based CRAC Cooled 2.67 0.69 1.9874.2% System w Containment CRAH Cooled 2.54 0.69 1.85 72.8% System wContainment Liquid Cooled 2.37 0.69 1.68 70.9% Racks Unoptimized LiquidCooled 1.72 0.69 1.03 59.9% Racks Chilled Water Temperatures OptimizedLiquid Cooled 1.39 0.69 0.70 50.4% Racks Chilled Water TemperaturesOptimized and Free Cooling Systems Liquid Cooled 1.21 0.69 0.52 43.0%Racks Chilled Water Temperatures Optimized and Evaporative Free CoolingSystems Active Liquid 1.17 0.69 0.48 41.0% Cooled Doors, Chilled WaterTemp Optimized, & Evaporative Free Cooling Systems Passive Liquid 0.930.69 0.24 25.8% Cooled Doors Chilled Water Temp Optimized & EvaporativeFree Cooling Systems Pumped Refrigerant 1.74 0.69 1.05 60.3% Systems AirSide Economizing 1.41 0.69 0.72 51.1%

TABLE 6 Energy Usage and Savings Comparison of Traditional Data CenterCooling Systems to the RTDCCS Annual Cooling Energy Cost CalculationElectric Energy Unit Cost USD 0.10 kWoflTLoad 2000 Tons of CoolingRequired 569 Energy Usage KW/ton Annual Energy Cost Traditional Mech. %Trad'l Mech. RTDCCS Cooling RTDCCS KW/Ton Energy Cooling Cooling KW/TonKW/Ton Savings Savings $/Year $/Year $ Savings CRAC Cooled System 2.880.69 2.19 76.0% $1,434,101 $343,926 ($1,090,175) RAH Cooled System- 2.730.69 2.04 74.7% $1,350,885 $343,926 ($1,006,959) Chilled Water BasedCRAC Cooled System 2.67 0.69 1.98 74.2% $1,331,452 $343,926 ($987,525)  w/Containment CRAH Cooled System 2.54 0.69 1.85 72.8% $1,262,413$343,926 ($918,486)   w/Containment Liquid Cooled Racks Unoptimized 2.370.69 1.68 70.9% $1,179,695 $343,926 ($835,769)   Liquid Cooled RacksChilled Water 1.72 0.69 1.03 59.9% $857,072   $343,926 ($513,146)  Temperature Optimized Liquid Cooled Racks Chilled Water 1.21 0.69 0.5243.0% $600,548   $343,926 ($256,622)   Temperature Optimized andEvaporative Free cooling Systems Active Liquid Cooled Doors, Chilled1.17 0.69 0.48 41.0% $583,008   $343,926 ($239,082)   Water TemperatureOptimized and Evaporative Free cooling Systems Passive Liquid CooledDoors, Chilled 0.93 0.69 0.24 25.8% $463,417   $343,926 ($119,490)  Water Temperature Optimized and Evaporative Free cooling Systems LiquidCooled Racks Chilled Water 1.39 0.69 0.70 50.4% $694,428   $343,926($350,501)   Temperature optimized and Free Cool- ing Systems PumpedRefrigerant Systems 1.74 0.69 1.05 60.3% $865,543   $343,926($521,617)   Air Side Economizing 1.41 0.69 0.72 51.1% $705,988  $343,926 ($362,062)  Multistage Evaporative Cooling System (MECS)

The MECS's new methods and systems allows the generation of cold makeupor process and/or comfort cooling supply air or cold cooling fluid, suchas water, at a low temperature, meeting the conditioned space'stemperature control requirements without adding moisture to the supplyair in most cases.

Main Features of the MECS are:

-   -   Design Simplicity (MECS does not need to rely on any        high-energy-using refrigeration compressors).    -   Ecologically sound design (MECS uses only water and atmospheric        air-no need to use Freon-type refrigerants such as        hydrochlorofluorocarbons (HCFCs)).    -   Scalability (MECS can be scaled to provide as little as 5 tons        to well over 500 tons of equivalent Conventional Mechanical        Refrigeration Cooling).    -   Economical Energy Use (MECS has significantly lower power        consumption compared to Conventional Mechanical Refrigeration        Systems).    -   Green Electrical Energy Use (MECS can use green electrical        energy sources (solar, wind, etc.).

FIG. 10 shows cooling tower 10, a Type-I cooling tower. Cooling tower 10comprises tower casing 15, cold-water reservoir 20, air inlet 35, airoutlet 40, water distribution system with nozzles 51, fan 55, pump 60,cold-water outlet 65, warm or spent water inlet 66, and mist eliminator71. Fan 55 is not present in some examples. Air inlet 35 sits near thebottom of cooling tower 10 in the embodiment depicted FIG. 10. Otherexamples can be envisioned in which air inlet 35 sits remotely fromcooling tower 10, but in those examples, ambient air should entercooling tower 10 below air outlet 40. Cold-water reservoir 20 sits nearthe bottom of cooling tower 10. But other examples exist in whichcold-water reservoir 20 sits remotely from cooling tower 10. In thosetypes of examples, one of ordinary skill in the art would recognize thatadditional piping and plumbing would be useful in such examples.

In some examples, airflow through cooling tower 10 is assisted by fan55. Fan 55 sits near the uppermost part of cooling tower 10 near airoutlet 40. Fan 55 may either be located downstream of mist eliminator 71or upstream of mist eliminator 71. Alternatively, a fan may mount at theinlet of cooling tower 10, pushing ambient air through cooling tower 10.Of course, a cooling tower could use two or more fans.

In some examples, water is distributed by the water distribution systemwith nozzles 51 over a mass heat transfer media (fill). In these typesof examples, one of ordinary skill in the art would recognize that massheat transfer occurs through the interaction between the water and airon the surface of the fill.

As stated previously, FIG. 10 depicts fan 55 on the top of cooling tower10. Mist eliminator 71 sits near the top of cooling tower 10 in theembodiment depicted in FIG. 10, as will be the case in most examplesthat employ a counter flow design. Some examples may use a cross flowcooling tower design, which would lead to a different arrangement of airinlets, water distribution systems, fans, etc. Water distribution systemwith nozzles 51 attaches to warm or spent water inlet 66, which connectsbetween cooling load Hat the warm outlet of air-to-water heat exchanger230 and water distribution system with nozzles 51. Pump 60 connects tocold-water reservoir 20 and connects to cooling loads 11 and an externalair-to-water heat exchanger, such as air-to-water heat exchanger 230,through cold-water outlet 65. Cold-water outlet 65 also connects to thecold-water inlet of air-to-water heat exchanger 230.

Invention cooling systems use a variety of cooling towers in addition tocooling tower 10.

FIG. 11 shows another type of cooling tower used in invention coolingsystems—cooling tower 210, a Type-II cooling tower. Cooling tower 210comprises tower casing 15′, cold-water reservoir 20′, air inlet 35′, airoutlet 40′, water distribution system with nozzles 51′, fan 55′, pump60′, cold water outlet 65′, warm water inlet 66′, mist eliminator 71′,and air-to-water heat exchanger 230.

Air-to-water heat exchanger 230 comprises a housing 231, heat exchangercold-water inlet 213, and heat exchanger warm water outlet 214. In someexamples, cold-water inlet 213 connects to cold-water outlet 65 and heatexchanger warm water outlet 214 connects to warm water inlet 66 of aType-I cooling tower. In other examples, cold-water inlet 213 connectsto cold-water outlet 65′ and heat exchanger warm water outlet 214connects to warm water inlet 66′ of a Type-II cooling tower.

Air inlet 35′ sits near the bottom of cooling tower 210, in theembodiment depicted by FIG. 11. Other examples exist in which air inlet35′ sits remotely from cooling tower 210 as long as ambient air enterscooling tower 210 below air outlet 40′. Air-to-water heat exchanger 230sits between air inlet 35′ and cooling tower 210. Cold-water reservoir20′ sits near the bottom of cooling tower 210. But other examples existin which cold-water reservoir 20′ sits remotely from cooling tower 210.In those types of examples, one of ordinary skill in the art wouldrecognize that additional piping and plumbing would be useful.

In some examples, fan 55′ assists air in flowing through cooling tower210. Fan 55′ sits on the top of cooling tower 210 near air outlet 40′.Fan 55′ may sit either downstream of mist eliminator 71′ or upstream ofmist eliminator 71′. Alternatively, a fan mounts at the inlet of coolingtower 210, designed to push ambient air through cooling tower 210. Ofcourse, this cooling tower may use two or more fans.

In some examples, water is distributed by the water distribution systemwith nozzles 51 over a mass heat transfer media (fill). In these typesof examples, one of ordinary skill in the art would recognize the massheat transfer interaction between the water and air on the surface ofthe fill.

Pump 60′ is in fluid communication with cold-water reservoir 20′ and influid communication with water distribution system with nozzles 51′,which is located near the uppermost part of cooling tower 210. In someexamples, “fluid communication” encompasses a cold-water outlet 65′connected to pump 60′. Cold-water outlet 65′ connects through anexternal device, comprising a pipe, heat exchanger, or other externaldevice (such as cooling load 11′), to warm water inlet 66′. In these orother examples, pump 60′ connects to cold-water reservoir 20′ andconnects to cooling loads 11′ and an external air-to-water heatexchanger, such as air-to-water heat exchanger 230′, through cold-wateroutlet 65′. Warm water inlet 66′ connects to water distribution systemwith nozzles 51′. In some examples, cold-water outlet 65′ connects to anexternal device such as an air-to-water heat exchanger mounted uponanother or an adjacent cooling tower or a cooling tower of anothercooling stage, and then continues on to water distribution system withnozzles 51′ through warm water inlet 66′.

In some examples, pump 60′ services water distribution system withnozzles 51′. In these or other examples, pump 60′ or another pump pumpscold water from cold-water reservoir 20′ to the cold-water inlet on anair-to-water heat exchanger mounted on another cooling tower and anotherpump pumps water-to-water distribution system with nozzles 51′.

FIG. 12 shows another type of cooling tower for use in invention coolingsystems—Cooling tower 310, a Type-III cooling tower. Cooling tower 310comprises tower casing 15″, cold-water reservoir 20″, air inlet 35″, airoutlet 40″, water distribution system with nozzles 51″, fan 55″, pump60″, pipe 65″, mist eliminator 71″, air-to-water heat exchanger 230′,and energy recovery system 330.

Air-to-water heat exchanger 230′ comprises a housing 231′, cold-waterinlet 213′, and heat exchanger warm water outlet 214′.

Air inlet 35″ sits near the bottom of cooling tower 310 in theembodiment depicted by FIG. 12. Other examples exist in which air inlet35″ sits remotely from cooling tower 310 as long as ambient air enterscooling tower 310 below air outlet 40″. Air-to-water heat exchanger 230′sits between air inlet 35″ and cooling tower 310. Cold-water reservoir20″ sits near the bottom of cooling tower 310. But other examples existin which cold-water reservoir 20″ sits remotely from cooling tower 310.In those types of examples, one of ordinary skill in the art wouldrecognize that additional piping and plumbing would be useful in suchexamples. As in cooling tower 210, various examples exist in whichcold-water reservoir 20 and cold-water reservoir 20′ are locatedremotely from cooling tower 10 and cooling tower 210, respectively.

In some examples, fan 55″ assists air in flowing through cooling tower310. Fan 55″ sits on the top of cooling tower 310 near air outlet 40″.Fan 55″ may sit downstream of mist eliminator 71″ or upstream of misteliminator 71″. Alternatively, a fan mounts at the inlet of coolingtower 310, designed to push ambient air through cooling tower 310. Ofcourse, a cooling tower may use two or more fans.

In some examples, water is distributed by the water distribution systemwith nozzles 51″ over a mass heat transfer media (fill). In these typesof examples, one of ordinary skill in the art would recognize that themass heat transfer interaction between the water and air on the surfaceof the fill.

Pump 60″ is in fluid communication with cold-water reservoir 20″ and influid communication with water distribution system with nozzles 51″located near the uppermost part of cooling tower 310. In some examples,fluid communication encompasses a pipe 65″, connected between pump 60″and water distribution system with nozzles 51″.

In some examples, pump 60″ services water distribution system withnozzles 51″. In these or other examples, pump 60″ or another pump pumpscold water from cold-water reservoir 20″ to a cooling load (such ascooling loads 11″ or a makeup air handling unit 715). Invention examplesmay cool any suitable cooling load (cooling loads 11″). Suitable coolingloads can be virtually any cooling load and include the following coolloads: environmental cooling (HVAC), building comfort cooling, processcooling, individual server enclosure/rack cooling, or any electronicsenclosure generating a heat load. In some examples, the cooling load isa make-up air-handling unit (MU Air Handling Unit or MUAHU). In someexamples, any cooling load that can be cooled with one or more coolingcoils is suitable for this invention.

In some examples, such as the embodiment depicted in FIG. 17, energyrecovery systems, such as energy recovery systems (ERS) 330 comprise awater circulation system comprising a pump 860 and an air-to-water heatexchanger 830. A particulate filter 831 sits upstream of air-to-waterheat exchanger 830, between an associated cooling tower and air-to-waterheat exchanger 830. After air-to-water heat exchanger 830 comes fan 835and finally outlet 836 to ambient air. ERS 330 connects to any suitablecooling load 811 through a closed-loop water circulation system. Thewater circulation system comprises air-to-water heat exchanger 830, warmwater inlet pipe 866, pump 860, cooling load 811, and cold-water outletpipe 865. Beginning with air-to-water heat exchanger 830, cold-wateroutlet pipe 865 connects to the output of air-to-water heat exchanger830 and connects to the cold-water inlet of cooling load 811. The warmwater outlet of cooling load 811 connects to pump 860. Pump 860 connectsto warm water inlet pipe 866, which in turn connects to the warm waterinlet of air-to-water heat exchanger 830. ERS 330 recovers “coolness”from the exhaust stream of an associated cooling tower. Since this is aclosed loop system, the water can be any suitable heat transfer fluidincluding a water and glycol mixture.

In some examples, energy recovery system 330 operates in conjunctionwith dampers 340, 341 in an associated cooling tower. Damper 340 sits inthe air outlet pathway and damper 341 sits in the ERS air pathway. Bothare disposed to allow the airflow to be adjusted from 100% through airoutlet 40″ and 0% through ERS 330, 0% air outlet 40″ to 100% through ERS330, or any air mixture or combination of mixtures. Any of the coolingtower examples described in this document may additionally comprise anenergy recovery system located at the air outlet of the cooling tower.

In any of the cooling tower types, one or more pumps may be variablespeed pumps or fixed speed pumps. In any of the cooling tower types, oneor more fans may be fixed speed fans or variable speed fans.

In addition to the components discussed above, the cooling towerscomprise monitoring and command-and-control hardware and optionallysoftware, to monitor and control the operation of the cooling towers.Various types of monitoring and command-and-control hardware andsoftware are familiar to those of ordinary skill in the art. Forinstance, variable speed fans have command-and-control hardware andsoftware that operate to vary the speed of fans to control airflowthrough the cooling towers. Variable speed pumps havecommand-and-control hardware and software to control the flow rate ofcold water from cold-water reservoir through the various othercomponents of the cooling tower and to cooling loads. Control over suchcomponents is based on the cooling needs of the cooling load, outsidetemperatures, etc. Control is exercised in some examples to run onlynecessary fans, pumps, etc. to meet the necessary cooling load withoutwasting energy. One category of energy that is saved because of theintervening command and control systems, is energy normally wasted byoperating fans, pumps, etc. faster or at a higher capacity thannecessary to satisfy the cooling load demands on the cooling system. Insome examples, components of the MECS are operated by a dedicatedcontrol system communicating with a building energy management system.The control software of the control system optimizes the operation ofthe cooling system components to meet variable or constant conditionedspace cooling loads, process-cooling loads, or other cooling loads atthe absolute lowest or minimum amount of energy consumption.

FIG. 13 depicts an embodiment of an invention cooling system. Coolingsystem 400 comprises three cooling towers: a Type-I cooling tower,cooling tower 401; a Type-II cooling tower, cooling tower 402; and aType-III cooling tower, cooling tower 403. Cold-water reservoir 20 ofcooling tower 401 connects through cold-water outlet 65 to cold-waterinlet 213, which connects to air-to-water heat exchanger 230 of coolingtower 402. Air-to-water heat exchanger 230 of cooling tower 402 connectsthrough heat exchanger warm water outlet 214 to warm water inlet 66,which returns warm water to cooling tower 401, as shown in the figure.In some examples, warm water returns to the water distribution systemwith nozzles 51 of cooling tower 401.

Cold-water reservoir 20′ of cooling tower 402 connects throughcold-water outlet 65′ to cold-water inlet 213′ of air-to-water heatexchanger 230′ of cooling tower 403. Air-to-water heat exchanger 230′connects through heat exchanger warm water outlet 214′, to warm waterinlet 66′, which returns warm water to cooling tower 402, as shown inFIG. 13. In some examples, warm water returns to the water distributionsystem with nozzles 51′ of cooling tower 402.

Cold-water reservoir 20″ of cooling tower 403 has cold-water outlet 65″that connects to the cold-water inlet of any suitable cooling load 11″.Likewise, warm-water returns through warm water inlet 66″ that connectsto the warm water outlet of cooling load 11″ to the water distributionsystem with nozzles 51″ of cooling tower 403.

Cold-water reservoir 20 of cooling tower 401 and cold-water reservoir20′ of cooling tower 402 may connect to optional cold-water supply andwarm-water return lines connecting to various different cooling loads11, 11′. One of ordinary skill in the art would choose which cold-waterreservoir (which cooling stage) to use based on the nature of thecooling load. In some examples, the cooling system comprises four ormore cooling towers.

FIG. 14 depicts cooling system 500, which is similar to cooling system400 of FIG. 13, discussed above. In addition to the components andconnectivity discussed for the cooling system above, this cooling systemcontains at least one energy recovery system 330 wherein the energyrecovery system 330 attaches to one or more cooling towers such ascooling towers 501, 502, 503 to recapture the “coolness” of cold airexiting from the cooling tower. In some examples, cooling system 500comprises a second or third energy recovery system 330, 330′ on thesecond or third cooling towers, such as cooling tower 502 or coolingtower 503. And in some examples, the cooling system comprises four ormore cooling stages with an energy recovery system on one or morecooling towers.

One typical, suitable cooling load for a cooling system such as coolingsystem 400 or 500 is a Make Up Air Handling Unit (MUAHU).

Makeup Air Handling Unit 715 comprises one or more air particulateFilters 750 at or near air inlet 720 of MUAHU 715. Following the airpath through MUAHU 715 air-to-air heat exchanger 745 is downstream ofair inlet 720 and air particulate Filters 750. Air-to-air heat exchanger745 comprises two air paths that do not mix with each other. One ofthose air paths relates to the makeup air and the other relates to thebuilding exhaust air. Fan 755 pulls building exhaust air throughair-to-air heat exchanger 745, and fan 735 pulls make up air throughair-to-air heat exchanger 745. An air-to-water heat exchanger 740 comesafter air-to-air heat exchanger 745 in MUAHU 715. A variable or fixedspeed supply fan 735 is disposed in MUAHU 715 downstream of air-to-airheat exchanger 740. In some examples, a direct evaporative or adiabaticwater humidifier (with mist eliminator) 730 sits near air outlet 731 ofMUAHU 715, just upstream of nozzles 732. Cold-water outlet 65″transports cold water from a cooling system to the cold-water inlet ofair-to-water heat exchanger 740. Warm water inlet 66″ transports warmwater from the warm water outlet of air-to-water heat exchanger 740 tothe cooling system.

In some examples, components of the MECS are operated by a dedicatedcontrol system communicating with a building energy management system.The control software of the control system optimizes the operation ofthe cooling system components to meet variable or constant conditionedspace cooling loads, process-cooling loads, or other cooling loads atthe absolute lowest or minimum amount of energy consumption. Executingthis software, the control system, depending on the conditioned spaceload, the process cooling load, or some other cooling load and indoorand outdoor air dry bulb and wet bulb temperatures, automaticallyprovides the necessary speed control over cooling towers fans, supplyair fans of makeup air-handling units, return and supply air fan, returnand supply air humidifiers, etc., and the necessary flow control overthe cooling fluids by controlling pumps, which are typical components ofcommercial, industrial, or other cooling systems. The control systemalso automatically adjusts all operational components of the MECS toachieve the amount of cooling needed for the load in real time tomaximum cooling efficiency.

In some examples, determined by the cooling application and theenvironmental conditions of the specific geographical area, componentsof the MECS are rearranged in an order and sequence and properly sizedto maximize the generation of cold water for given environments. Thesecooling applications or any kind of cooling application in commercialreal estate buildings, industrial real estate buildings, and governmentreal estate buildings; manufacturing plants; industrial processingplants; food/beverage processing plants and agricultural buildings.

In some examples, an individual electronics enclosure cooling systemuses cold water generated by the different stages of the MECS to applyprocess cooling method to each cooling load in each individualelectronics enclosure. In some examples, invention-cooling systems areoptimized for providing cold water to individual electronics enclosuresor racks, such as server racks to cool the loads. The electronicsenclosure is designed to allow space air to be drawn in to cool theelectronics equipment inside the enclosure through an air inlet andfurther pulled through the enclosure to an air outlet exit point. Thewarm air, which was heated by the electronics within the enclosure,exits the air outlet of the enclosure and enters into an air inlet ofone or more fan coils units. There the warm air is cooled by circulatingcooling water such as from an invention cooling system, i.e. cold waterfrom different stages of the MECS, before the cooled air is returned tothe space from the air outlet of the fan coil unit.

Cooling system examples exist comprising 2-10 2-5, 5, 4, 3, or 2 typesof cooling towers or cooling tower cells. Each of these examplescomprises 0, 1, or 2 energy recovery system per cooling tower.

Operation of MECS System

Operationally, any cooling tower suitable for use with the coolingsystems of the current invention operates as described below. A coolingtower cools incoming ambient air and water from the cold-water reservoir20. Fan 55 assists in moving air through the cooling tower. Ambient airenters the cooling tower through air inlet 35 and exits the coolingtower at the top through air outlet 40. As the fan pulls air into thecooling tower, water distribution system with nozzles 51 introduceswater on top of the fill through water distribution system nozzles 51causing or allowing contact between the moving ambient air and thefalling liquid water within the fill. The cooled falling liquid water iscollected in the cold-water reservoir 20 and the saturated cold airexits the cooling tower through air outlet 40.

Pump 60 pumps water from cold-water reservoir 20 through cold-wateroutlet 65 to a cooling load, such as air-to-water heat exchanger 230.After moving through the cooling load, the now warmer, cold watertravels through warm water inlet 66 into water distribution system withnozzles 51 located above the fill of cooling tower 10. Water fallingfrom the top of cooling tower 10 passes by ambient air moving from airinlet 35 at the bottom of cooling tower 10 to air outlet 40 at the topof cooling tower 10. Fan 55 moves air through cooling tower 10.

This air-water interaction causes some water to evaporate. Waterevaporation requires energy, in this case, the energy is extracted fromthe water flowing through the fill, leaving the water at a lowertemperature and the air exiting air outlet 40 at DB temperature lowerthan ambient air temperature. That is, the air-water interaction lowersthe temperature of the air as the air passes through the cooling tower.Cold water falls to the bottom of cooling tower 10 and collects incold-water reservoir 20.

All psychometric parameters of the given air have direct correlationwith each other in any kind of cooling apparatus. Knowing the dry bulbtemperature, the wet bulb temperature, and the barometric pressure ofthe air allows the determination of all other parameters of the air suchas enthalpy, relative humidity, dew point temperature, absolute moisturecontent, specific volume, etc. For a particular sample of air, themaximum wet bulb temperature is equal to the dry bulb temperature.Larger differences between the dry bulb temperature and the wet bulbtemperature indicate drier air.

One of ordinary skill in the art knows that adiabatic cooling of aparticular sample of ambient air equal to or below its wet bulbtemperature is not possible. During the adiabatic air cooling process,the air's dry bulb temperature is lowered and its moisture content isincreased, however, its wet bulb temperature and enthalpy do not change.This has ramifications in using evaporative cooling towers.

Cold-water reservoir 20 located near the bottom of cooling tower 401feeds cooling loads 11. The warm water from cooling load 11 connects towarm water inlet 66, and to water distribution system with nozzles 51 ofcooling tower 401 completing the cycle. Gravity causes the water to fallthrough the cooling tower fill back into the cold-water reservoir.During this trip, the water again interacts with the air flowing upthrough the cooling tower and is in direct contact with the air flowingthrough the cooling tower. The main result from this air-water contactis that, as before, some amount of the water evaporates in the airflowing up through the cooling tower. And the cycle continues. Thedifference between the dry bulb temperature and the wet bulb temperatureis smaller after passing through the cooling tower. Therefore, one ofordinary skill in the art recognizes that the trip through the coolingtower lowers the temperature of the water.

Each of the multiplicity of invention cooling towers operates in thismanner. The temperature of the cold water generated by any cooling toweris dependent on the wet bulb temperature of the air entering the coolingtower. The cooling towers use ambient air during operation. Therefore,the only way of attaining cold water temperatures lower than the wetbulb temperature of the ambient air, is to lower the wet bulb and drybulb temperatures of the ambient air entering the cooling tower. Inother words, sensible pre-cooling of the ambient air entering thecooling tower reduces its wet bulb and dry bulb temperature therebyallowing colder water temperatures to be achieved at each cooling stage.

The Type-II cooling towers and Type-Ill cooling towers add sensiblepre-cooling of the ambient air entering the cooling towers through anair-to-water heat exchanger at their air inlets. These air-to-water heatexchangers, also called pre-cooling heat exchangers sit between theirrespective air inlet and respective cooling tower. A cold-waterreservoir of another stage of the cooling system or of a previous stageof the cooling system provides cold water for the air-to-water heatexchanger. As ambient air passes through the heat exchanger, it coolsand water from the cold-water reservoir warms. The water returns to thesource cooling tower water distribution system with nozzles 51continuing the cycle. The source cooling tower ultimately removes theheat gained by the cold water as it passed through the air-to-water heatexchanger.

The ambient air passes through the air-to-water heat exchangers whichlowers the wet bulb and dry bulb temperatures of the air entering theType-II or Type-Ill cooling towers. Since the wet bulb temperatureserves as the lower limit for the temperature of the cold-water in thiscooling towers and since the wet bulb temperature of the pre-cooled airis lower than that of the incoming ambient air in a previous coolingstage, the Type-II or Type-Ill cooling tower produces cold water with atemperature lower than cold water produced by an earlier cooling stage.This ability of a later cooling stage to produce colder water than anearlier cooling stage stems directly from the fact that the sensiblepre-cooling of ambient air without exposing it to added moisturesimultaneously drops the air's dry bulb and wet bulb temperatures.Dropping the wet bulb temperature of each stage's air entering thecooling towers lowers the temperature of the cold water produced bythese stages. Thus, cascading cooling towers allows the cooling systemto produce lower temperature cold water in each of the successivestages.

Returning to FIG. 13, the cooling system functions to produce cold waterto service cooling loads 11, 11′, 11″, and the cooling load resultingfrom MU Air Handling Unit 715. In cooling tower 401, fan 55 operates topull air ambient air through air inlet 35, through air-to-water heatexchanger 230, through the wet fill, past the water distribution systemwith nozzles 51, through the mist eliminator 71, up through the fan 55,and finally out air outlet 40. Simultaneously with air moving up throughthe cooling tower 401, pump 60 pumps cold water from cold-waterreservoir 20, through cold water outlet 65, connected to inlet waterpipe 213, through air-to-water heat exchanger 230 on cooling tower 402,out air-to-water heat exchanger 230, through outlet water pipe 214connected to warm water inlet 66, and, completing the cycle, to waterdistribution system with nozzles 51 of cooling tower 401. Waterdistribution system with nozzles 51 distributes water evenly across thetop of the fill of cooling tower 401. The water falls by gravity throughthe fill of cooling tower 401 to cold-water reservoir 20. As cold waterfrom cold-water reservoir 20 moves through the system, it provides asource of indirect sensible pre-cooling for air entering cooling tower402 through air-to-water heat exchanger 230. The warmed water isreturned to cooling tower 401 via the water distribution system withnozzles 51.

Fan 55′ of cooling tower 402 operates to pull ambient air into coolingtower 402 through air inlet 35′, through air-to-water heat exchanger230, through the wet fill, past the water distribution system withnozzles 51, through the mist eliminator 71, up through fan 55′, andfinally out air outlet 40′ of cooling tower 402. Water from waterdistribution system with nozzles 51′ distributes water evenly across thetop of the fill of cooling tower 402. As the water falls by gravitythrough the fill of cooling tower 402, it interacts with the movingpre-cooled air stream that has been pre-cooled by air-to-water heatexchanger 230. The air-water interaction within cooling tower 402 causessome water to evaporate. This evaporation extracts (heat) energy out ofthe circulating water stream and transfers this energy to theinteracting air stream of cooling tower 402. The cold water obtained bythe result of the above air-water interaction is collected in cold-waterreservoir 20′. The journey of the cold water begins again as pump 60′pumps water from cold-water reservoir 20′ through cold-water outlet 65′,to pipe 213′ into air-to-water heat exchanger 230′, out pipe 214′,through warm water inlet 66′, into water distribution system withnozzles 51′. Since cooling tower 402 operates with an air streamcomprising air with a lower wet bulb temperature and dry bulbtemperature (because of the air's trip through air-to-water heatexchanger 230), the achievable temperature of the cold water in coldwater reservoir 20′ is substantially lower than the temperature that thecold water of cold water reservoir 20 can achieve.

As described above for tower 402, fan 55″ of cooling tower 403 operatesto pull ambient air into air inlet 35″, through air-to-water heatexchanger 230′, through the wet fill, past the water distribution systemwith nozzles 51″, through the mist eliminator 71″, up through fan 55″and finally out air outlet 40″ of cooling tower 403. Pump 60″ pumpswater from cold-water reservoir 20″, through pipe 65″, to cooling loads11″ and MU Air Handling Unit 715. The warm water from the above loads isreturned back to cooling tower 403 through pipe 66″. Pipe 66″ connectsto the water distribution system with nozzles 51″ of cooling tower 403,which evenly distributes water across the top of the fill. As the waterfalls by gravity through the Pill of cooling tower 403, it interactswith the moving pre-cooled air stream that has been pre-cooled byair-to-water heat exchanger 230. The air-water interaction withincooling tower 403 causes some water to evaporate. This evaporationextracts (heat) energy out of the circulating water stream and transfersthis energy to the interacting air stream of cooling tower 403. The coldwater obtained by the result of the above air-water interaction iscollected in cold-water reservoir 20″. The journey of the cold waterbegins again as pump 60″ pumps water from cold-water reservoir 20″ tocooling loads 11″ and MU Air Handling Unit.

The first cooling state, comprising cooling tower 401, produces coldwater that approaches the wet bulb temperature of the ambient air. Thiscold-water services air-to-water heat exchanger 230, a pre-cooling heatexchanger, located at air inlet 35′ of cooling tower 402. Cooling tower402 composes part of cooling stage 2. Since the cooling system operatesto provide pre-cooled air ultimately to cooling tower 402, when coolingstage 2 comprising cooling tower 402 operates, it produces water that iscolder than the cold water produced by cooling stage 1. This colderwater ultimately provides cooling tower 403 with air that has an evenlower wet bulb and dry bulb temperature than previous stages allowingcooling tower 403 to produce cold water that is even colder than thecold water produced in the second cooling stage.

Each of cooling towers 402 and 403 uses pre-cooled air that has a lowerwet bulb temperature than ambient air. Using the pre-cooled air allowsthese cooling towers to reach significantly lower cold-watertemperatures and exhaust air temperatures than cooling towers withoutair pre-cooling. In some examples, the cold exhaust air exiting thecooling towers is utilized as a source of energy by the Energy RecoverySystems to produce further useable cold water or cold air and to produceadditional energy savings as compared to traditional cooling methods.Such an embodiment is depicted in FIG. 14.

The cooling system depicted in FIG. 14 functions substantially similarlyto that of the cooling system of FIG. 13.

In addition to the cold water generated by the cooling towers, such ascooling towers 501, 502, 503, the cooling towers generate exhaust airthat is colder than ambient air and can be utilized as a significantenergy source for additional cooling loads. The exhaust air exits thecooling towers through air outlets 40, 40′, 40″. In some examples,dampers 340, 340′, 340″ control exhaust air flow out of the respectivecooling towers. These dampers divert the exhaust airflow from coolingtower air outlets 40, 40′, 40″. Dampers 340, 340′, 340″ can directexhaust air streams in the following optional ways. Option A—the dampersdirect 100% of the exhaust air through energy recovery systems 330,330′, and 330″. Option B—the dampers direct 100% of the exhaust airthrough air outlet 40, 40′, 40″ to the outside atmosphere bypassing theenergy recovery systems. Option C—based on cooling load demands, thedampers split the exhaust air stream in any desired ratio between energyrecovery systems 330, 330′, 330″ and exhaust air outlets 40, 40′, 40″.

As seen in FIG. 17, energy recover system 330 functions to reclaim someof the “coldness” from the cooling tower exhaust air by using internalfan 835 to move cool exhaust air past air-to-water heat exchangers 830in ERS 330. This cold source can be used to service any appropriatecooling load that one of ordinary skill in the art would considersuitable. Warm water enters air-to-water heat exchangers 830 throughwarm water inlet pipe 866 and travels through air-to-water heatexchangers 830 where the water gives offheat to the air stream flowingout of the cooling tower. Next cold water flows from the cold-wateroutlet of air-to-water heat exchangers 830 into cold-water outlet pipe865. Cold-water outlet pipe 865 carries the cold water to the cold-waterinlet of cooling load 811 where the cold water picks up heat fromcooling load 811 and flows through the warm water outlet of cooling load811, through pump 860 into warm water inlet pipe 866 to begin the cycleagain. Pump 860 drives the flow through the closed loop system.

To present a better understanding of the design and operationalspecifics of the MECS, demonstration of its cooling capability andperformance, and for eventual comparison with a Conventional MechanicalRefrigeration System, the following design conditions are used toprovide a comparable engineering analysis for both systems performingequal tasks:

EXAMPLES Example 1 Cooling Application

-   -   Cool a conditioned space with the summer design sensible cooling        load of approximately 92 tons of equivalent refrigeration.    -   Project Location—Phoenix, Ariz.    -   The ASHRAE specified design ambient air parameters for Phoenix        Ariz. for cooling applications are 110.2° F. DB and 70° F. WB.    -   The ASHRAE specified design ambient air parameters for Phoenix        Ariz. for evaporation applications for 0.4% are 76.1° F. WB and        96.4° F. MCDB (Mean Coincident dry bulb temperature). (For        reference only)    -   The indoor design air temperature is approximately 80° F. DB at        a comfortable 40 to 65% relative humidity range.    -   The preliminary estimate of required volume of makeup/supply        cooled air into the conditioned space is approximately 35,000        CFM.

These calculations are provided as illustrative example only for theexemplary system described herein. They do not limit the invention inany way and are only provided to guide the user in implementing otherequivalent implementations of the invention.

Typical MECS engineering design and component list selected forperforming the above-mentioned cooling.

The MECS is configured for this particular application, and it consistsof the following main components:

-   -   Three induced draft counter flow cooling towers or comparable        Air Washers; variable speed exhaust air fans; and variable flow        circulating water pumps; and.    -   Pre-cooling coils located at the ambient air inlets of the        cooling towers.

The components of makeup air-handling unit 715 sit in the followingsequence and following the airflow direction. Powered by a fixed orvariable speed supply fan 735, ambient air passes through the air inlet720 of makeup air-handling unit 715. Then it passes through airparticulate filter(s) 750 and air-to-air heater exchanger 745. Airflowthrough air-to-air heat exchanger 745 is assisted by fan 755. Thisairflow is building exhaust air, which pre-cools ambient air destinedfor introduction into the building. Next, it reaches cooling coil 740.Cold water is pumped from a cooling stage of a cooling system, throughpipe 65′ through the cold-water inlet 213 to cooling coil 740 of makeupair-handling unit 715 and then through the heat exchanger warm wateroutlet 214 to pipe 66′ back to the cooling system. As air passes overcooling coil 740, it gives offheat to the cold water causing thetemperature of the air to fall providing sensible cooling.

In applications where the space does not required 100% ambient air butstill has the same space cooling load, the air-to-air heat exchanger 745could be replaced with an air-mixing module (not shown). The air-mixingmodule mixes large volumes of lower temperature return air from theconditioned space with the minimal required volume of ambient air(ventilation air). This mixed air application will significantly reducethe total energy consumption of the MECS. (Note: If this air-mixingapplication is implemented, the need for humidification is greatlyreduced or eliminated in most cases.)

Return Air Sub-System (RA Sub-System)—the RA Sub-System containsductwork, an adiabatic humidification chamber, and return air exhaustfan. The RA Sub-System controls temperature, humidity, and air volume ofthe return air stream being fed to one side of the air-to-air heatexchanger 745 or to the air-mixing module.

The integrated MECS contains the following sequential process coolingstages:

Cooling Stage-1 (Water Cooling)

From FIG. 15, this cooling stage comprises cooling tower 601 and a waterpump 60. Cooling tower 601 generates cold water that collects in itscold-water reservoir 20. Cooling stage-1 generates cold water forpre-cooling ambient air entering into the next stage cooling towers. Thecooling coil (air-to-water heat exchanger 230) pre-cools ambient airentering into the next stage cooling tower 601′ using some of the coldwater from cooling tower 601.

Cooling Stage-2 (Water Cooling)

This cooling stage comprises a second cooling tower 601′, a water pump60′, and a cooling coil (air-to-water heat exchanger 230′). Coolingtower 601′ generates cold water that collects in its cold-waterreservoir 20′ and supplies cold water to the air-to-water heat exchanger230′ of the third cooling tower 601″.

Cooling Stage-3 (Water Cooling)

This cooling stage comprises third cooling tower 601″, a water pump 60″,and a cooling coil (air-to-water heat exchanger 230′). Cooling tower601″ generates cold water that collects in its cold-water reservoir 20″,and supplies cold water to a cooling coil (air-to-water heat exchanger740) installed in the housing of makeup air-handling unit 715 or someother cooling load or process cooling load.

Cooling Stage-3 (Water Cooling)

This cooling stage comprises a cooling coil (air-to-water heat exchanger740) installed in the makeup air-handling unit. The cooling coil(air-to-water heat exchanger 740) receives cold water from third coolingtower 601″. The cooling coil (air-to-water heat exchanger 740) sits inthe housing of makeup air-handling unit 715 downstream of an air-to-airheat exchanger 745 and can either cool air leaving the air-to-air heatexchanger 745 or, if the air-to-air heat exchanger is not included,precools warm ambient air as it enters into the makeup air-handling unit715.

Cooling Stage-5 (Makeup Air Cooling)

This stage is the final cooling stage inside of the makeup air-handlingunit 715. It provides adiabatic cooling of the supply air using anysuitable direct evaporative cooling system 732, such as using highpressure fogging nozzles.

Cooling Stage-6 (Return Air Cooling)

This cooling stage is a part of the return air RA Sub-System, combiningthe return air (RA) ductwork, evaporative air humidification chamber,and the RA exhaust fan. The humidification chamber comprises ahumidifier that could be either a high-pressure water dispersion type,or any other evaporative humidifier type appropriate for theapplication. The purpose of cooling stage-6 is to providehigh-efficiency adiabatic cooling of the RA stream before its heatexchange interaction with the warm ambient air stream in the air-to-airheat exchanger 745, or before mixing with ambient air (ventilation air)in the air-mixing module, if the cooling system is configured to use anair-mixing module.

Cooling Stage-7 (Makeup Air Cooling)

This cooling stage is an air-to-air heat exchanger and its function isto pre-cool outside warm air using the lower temperature return airstream from the conditioned space and thereby reduce the MECS totalenergy use.

Different cooling applications call for varying MECS configurations.

Each MECS is configured to produce the required amount of cooling for adefined application, such as conditioned space or process cooling forindustry. Each design factors in the peak cooling demand at summerconditions for the local environment.

The MECS has a dedicated control and monitoring system with appropriatesoftware to provide optimum, moment-to-moment control over operatingparameters that yield the required amount of cooling at minimal powerconsumption based on constantly changing building cooling loads, processcooling loads, and ambient air conditions.

MECS Cooling Stages—Divided into Water and Air Cooling Stages

Described in a different way, in general, all cooling stages of MECSfall into two states: a water-cooling stage and an air-cooling stage.

A. Water Cooling Stages

The three water-cooling stages of the MECS use three cooling towers601,601′,601″ with each stage having a cooling tower, a cooling coil(optional in the first cooling tower), and a pump arranged in series toprovide a cascade of cooling stages. That is, the cooling tower of apreceding stage generates cold water similarly to prior art coolingtowers. This cold water is used to pre-cool the incoming air of asucceeding stage, allowing the cooling tower of the succeeding stage toproduce cooler water than was possible in the preceding stage. In someexamples, this cascading of one cooling tower after another with a lowerstage bolstering the cooling ability of a higher stage continues, givingcooling systems with 3, 4, 5, or more successive stages, each stagecapable of producing cold water at successively colder temperatures.

MECS operation begins with a command from the central computer of theenergy management system and from the local programmable logiccontroller. The operation of the MECS takes place in the followingsequential steps:

Step-1

The fan 655 of the first cooling tower 601 starts, using a slow startmethod. Water circulating pump 60 starts, using a slow start method. Thepump 60 takes cold water from the cold-water reservoir 20 and directsthe water to pre-cooling coils (air-to-water heat exchanger 230′)installed at the ambient air intakes of another cooling tower(s),respectively. Water, warmed by pre-cooling coils, returns to the sourcecooling tower and distributes the water evenly over the top of coolingtower fill, positioning it for continuing the evaporative cooling cycle.

Step-2

The fan 655′ in the second cooling tower 601′ starts, using a slow startmethod. The water-circulating pump 60′ starts, using a slow startmethod. The pump 60′ takes cold water from cold-water reservoir 20′ anddirects the water to pre-cooling coil (air-to-water heat exchanger 230′)installed at the ambient air intakes of the next stage cooling tower601″. Warmed water from the pre-cooling coil returns to the sourcecooling tower 601′ and distributes the water evenly over the top of thefill of the cooling tower for continuing the evaporative cooling cycle.

Step-3

The fan 655 “of the third cooling tower 601” starts, using a slow startmethod. The water circulating pump 60″ starts, using a slow startmethod. The pump 60″ takes cold water from the cold-water reservoir 20″and directs the water to pre-cooling coil (air-to-water heat exchanger740′) installed in the makeup air-handling unit 715. The warm water fromthe pre-cooling coil returns to the source cooling tower 601′ anddistributes the water evenly over the top of the fill for continuing theevaporative cooling cycle.

Due to the heat-mass transfer process taking place in the fill of allcooling towers, part of the water falling over the cooling tower fillevaporates and this evaporation process lowers the temperature of theremaining water that is falling through the cooling tower and collectedin the cold-water reservoirs. The dry bulb temperature of ambient airentering into the pre-cooling coils is higher than the temperature ofthe cooling coil cooling water. The precooling coils extract some amountoffheat from the ambient air and, as a result, the dry bulb and wet bulbtemperatures of the ambient air falls (is lowered). The calculations forthe embodiment assume approach temperatures for cooling towers 2° F.,and approach temperatures for pre-cooling coils 3° F.

These approach temperatures have been selected as illustrative examplesonly for the exemplary system described herein. Other approachtemperatures may be applied that will provide a varying degree ofresults. The cooling towers may have approach temperatures that aredifferent from one another or that are the same. Pre-cooling coils mayhave approach temperatures that are different from one another or thatare the same.

Step-4

Supply fan 735 of makeup air-handling unit 715 starts, using a slowstart method.

Step-5

The RA exhaust fan of the RA Sub System starts, using the slow startmethod.

Step-6

After the cooling system achieves the desired cold air supply from themakeup air-handling unit and achieves the desired temperature for theair leaving the pre-cooling coil, the control system, based onestablished parameters, activates the humidifier 730 at its minimumcapacity and gradually adjusts its humidification capacity to humidifyair as set out in the specific design specifications of the applicationfor the conditioned space.

Step-7

After the cooling system achieves the desired cold air supply from themakeup air-handling unit 715, the control system adjusts and regulatesthe return air fan to meet the desired volume of return air.

Step-8

After the supply and return airflows are balanced as desired, thecontrol system activates the humidifier in the RA Sub System at itsminimum capacity and gradually adjusts its humidification capacity untilit optimizes the humidification level to provide the lowest possibletemperature of the return air stream. Lower air stream temperatures atthis point provide maximum pre-cooling of ambient air in the air-to-airheat exchanger.

Example 2

The following estimates show cold water temperatures leaving the coolingtowers for a cooling system design based on summer ambient airconditions for Phoenix, Ariz., and according to the MECS (coolingsystem) design. Since ASHRAE-specified design ambient air parameters forPhoenix, Ariz., for evaporation applications for 0.4% are 76.1° F. WBand 96.4° F. MCDB (evaporative application) exist at peak conditions foronly a very short cooling time, these analysis and calculations focus onthe ASHRAE Cooling Application corresponding to ambient air parametersfor Phoenix, Ariz., of 110.2° F. DB and 70.0° F. WB temperatures. Theseparameters approximate some of the least favorable conditions for usingevaporative cooling systems in Phoenix.

The estimated theoretical temperatures of cold water exiting any coolingtower with a design approach temperature of 2° F. operating at thedesign ambient air conditions of 76.1° F. WB and 96.4° F. MCDB(evaporative application) without using pre-cooling coils isapproximately 78.1° F.

The estimated theoretical temperatures of cold water exiting a similarlydesigned cooling tower operating while not using a pre-cooling coil andcooling towers operating while using pre-cooling coils at the designambient air conditions of 76.1° F. WB and 96.4° F. MCDB (evaporativeapplication) are approximately 78.1° F., 73.6° F. and 72.6° F.,respectively.

The estimated theoretical temperatures of cold water exiting any coolingtower with a design approach temperature of 2° F. (operating withoutpre-cooling coils) at the design ambient air conditions of 110° F. DBand 70° F. WB (cooling application) is approximately 72° F.

The estimated theoretical temperatures of cold water exiting a similarlydesigned cooling tower operating while not using a pre-cooling coil andsecond and third stage cooling towers operating while using pre-coolingcoils at the design ambient air conditions of 110° F. DB and 70° F. WB(cooling application) are approximately 72° F., 60.2° F. and 55.5° F.,respectively.

The design approach temperature for all the cooling towers is 2° F. Thedesign approach temperature for all cooling coils in this calculation is3° F. But approach temperatures may change to meet specific coolingdesign applications for specific locations and design parameters andwill result in varying cooling results.

It should be noted that the estimated temperature values of cold watershown above for the cooling and evaporative applications does notinclude the pre-cooling of ambient air in the cooling coil located atthe air intake of the first cooling tower. If the MECS design includesthe cooling effect of the cooling coil, the water temperatures leavingthe next stage cooling towers would be lower.

Sequential Cold Water Temperature Chain of the MECS Water Cooling Stages

The temperature of cold water exiting the third cooling tower isapproximately 55.5° F., lower than the temperature of cold water exitingthe second cooling tower, and the temperature of cold water exiting thesecond cooling tower is approximately 60.2° F., lower than thetemperature of cold water exiting the first cooling tower, which isapproximately 72° F. Another means of stating the above is that thetemperature of cold water exiting cooling towers is that the thirdcooling tower is approximately 55.5° F., which is less than the secondcooling tower of approximately 60.2° F., which is less than the firstcooling tower of approximately 72° F. In this design example, theinitial ambient air wet bulb temperature is 70° F. Therefore, in thisexample, an invention cooling system provides evaporatively cooled coldwater exiting the final cooling tower at approximately 55.5° F., whichis lower than the 70° F. initial wet bulb temperature of the ambientair.

Some invention cooling systems achieve these effects using variousmethods and systems consisting of the following:

Pre-cooling the ambient air entering into the cooling tower(s) withcooling coil(s) to provide sensible cooling of the entering air forlowering the ambient air's dry bulb and wet bulb temperatures.

If more than one cooling tower is arranged in series (cascaded) to meeta specific application, cold water from a first stage cooling tower issupplied to the cooling coil of the second cooling tower and to otheroptional cooling loads. Cold water from a second-stage cooling tower issupplied to the cooling coil to a third or subsequent stage coolingtowers and to other optional cooling loads. Cold water from a second,third, or greater stage is supplied to the cooling coil in the makeupair-handling unit and may be supplied to other optional cooling loads.

For the specific local design conditions and specific coolingapplication, the piping system configuration supplying cold water orcold air to the air or water cooling loads can be modified to provideflexibility in operating any combination of cooling towers.

In all cases, invention methods of arranging the cooling towers in aseries/cascade providing for the operation of the cooling towercombinations using special direct/indirect evaporation techniques isable to generate cold water with a final temperature lower than theinitial wet bulb temperature of ambient air. The temperature of coldwater generated by MECS can be used to satisfy a majority of HVAC andprocess cooling applications while using significantly lower energy ascompared to conventional mechanical refrigeration systems.

Air Cooling Stages

The makeup air-handling unit cools the makeup air for this particularapplication. The makeup air-handling unit comprises a pre-cooling coilproviding sensible cooling (cooling stage-4) of the ambient air, anevaporative humidifier providing additional (if necessary) adiabaticcooling of the makeup air (cooling stage-5), and either an air-to-airheat exchanger (cooling stage-7) or air-mixing section or both use thereturn air from the conditioned space.

The makeup air-handling unit fan pulls the required amount of the makeup(ambient) air into the makeup air-handling unit housing through the airintake louver. The air then passes through the air filter section, theair-to-air heat exchanger section, and enters into the pre-cooling coil,which cools makeup air using cold water supplied from cooling tower.(Note: At this point, it is not assumed that an air-to-air heatexchanger is incorporated thereby facilitating the next statement.) Airenters pre-cooling coil at conditions of 110.2° F. DB and 70° F. WBtemperature and leaves pre-cooling coil at approximately 58.5° F. DB and51.5° F. WB temperature. The sensible cooling load for pre-cooling coilfor a cooling application described herein is approximately 168.0 tonsof equivalent refrigeration.

Note: For demonstration of the available cooling capacity of the MECS,we do not take into consideration the heat rejected from the ambient airstream by pre-cooling the return air stream in the air-to-air heatexchanger.

Cooling Stage-5 (Makeup Air Cooling)

Cooling Stage-5 further increases cooling capacity of the cooled supplyair, reducing its dry bulb temperature by means of adiabatic cooling ofambient air coming through the pre-cooling coil. Cooling Stage-5comprises an evaporative air humidifier installed in the makeupair-handling unit housing downstream of the supply air fan. Theadiabatic cooling capacity of cooling stage-5 is approximately 96,485BTU/hr or 8 tons of equivalent refrigeration. The humidifier could beeither a high-pressure water dispersion type or any other type ofevaporative humidifier appropriate for the application. The integratedpart of the cooling stage-5 is a mist eliminator situated downstream ofthe humidifier. The parameters of the supply air leaving cooling stage 5and entering into the conditioned space are approximately 51.8° F. DBand 51.3° F. WB at the total supply airflow rate of approximately 35,000CFM (air mass flow is equivalent to 160,809 lbs/hr). Assuming acondition space temperature of 80° F. DB, the assimilating sensiblecooling capacity of the supply air is approximately 92 tons ofequivalent refrigeration.

Cooling Stage-6 (Return Air Cooling)

The air cooling stage-6 provides the high-efficiency adiabatic coolingof the RA stream to reduce its temperature as low as possible before itsheat exchange interaction with the warm ambient air stream in theair-to-air heat exchanger which is part of cooling stage-7. This aircooling stage-6 is a part of the RA Sub-System, combining the RAductwork, evaporative air humidification chamber, and the air-to-airheat exchanger physically located in the makeup air-handling unithousing. The humidification chamber comprises the humidifier, whichcould be either a high-pressure water dispersion type or any otherappropriate type of evaporative humidifier matching the application. Theintegrated part of cooling stage-6 is a mist eliminator situateddownstream of the humidifier in the humidification chamber.

Cooling Stage-7 (Makeup Air Cooling)

Cooling Stage-7 allows significant reduction in the total energy usageby the MECS, especially at peak conditions, by pre-cooling ambient airusing the lower temperature return air from the conditioned space. Inour case, the estimated temperature of the adiabatically cooled RAentering the air-to-air heat exchanger could be within approximately75-76° F. DB range while the temperature of ambient air entering theair-to-air heat exchanger is 110.2° F. DB. The anticipated heat transferefficiency of the heat exchanger with the above interacting air-streamsis approximately 70%.

Cooling Stage-7 consists of an air-to-air heat exchanger situated atambient air intake of the makeup air-handling unit, RA exhaust fan, andRA ductwork. The RA exhaust fan is installed at the strategiclocation-downstream of the air-to-air heat exchanger. This location ofthe RA exhaust fan makes the following positive energy impacts:

It increases the total amount of heat extracted from the warm ambientair stream by eliminating the fan heat going to the RA stream resultingin the production of cooler makeup air entering into pre-cooling coiland reducing the cooling load on the pre-cooling coil.

It decreases the required amount of cold water used by pre-cooling coil,and reduces the energy consumption of all the operating cooling towersand their respective water circulating pump(s).

The makeup air-handling unit of the MECS supplies into the conditionedspace approximately 35,000 CFM of cooled air at the estimated parametersof 51.8° F. DB and 51.3° F. WB. The initial design parameters of ambientair entering into the makeup air-handling unit are 110.2° F. DB and 70°F. WB temperatures. The indoor air design parameters for the conditionedspace are approximately 80° F. DB and 62.3° F. WB temperatures. Thecooling capacities of the air cooling stages of the makeup air-handlingunit are:

-   -   Air Cooling Stage-4 168 tons of equivalent refrigeration.    -   Air Cooling Stage-5 (sensible equivalent adiabatic cooling) 8        tons of equivalent refrigeration.

The total gross air cooling capacity of the makeup air-handling unit inthis example is approximately 176 tons of equivalent refrigeration. Thetotal sensible cooling load for cooling 160,809 lbs/hr of ambient airmass at initial temperatures of 110.2° F. DB and 70° F. WB to supply airtemperatures of 51.8° F. DB and 51.3° F. WB is approximately 170 tons ofequivalent refrigeration. Therefore, to cool specified amounts ofambient air from the initial design parameters to the specifiedparameters of the supply requires a net of approximately 170 tons ofequivalent refrigeration.

35,000 CFM (mass flow rate 160,809 lbs/hr) of supply air at approximateconditions of 51.8° F. DB and 51.3° F. WB temperatures can providespecified indoor air conditions of 80° F. DB and relative humidity of62.3% in the conditioned space. The corresponding net sensible coolingcapacity of the cold supply air is approximately 92 tons of equivalentrefrigeration.

Note: The design parameters of the return air exiting the conditionedspace and entering into RA Sub-System are approximately 80° F. DB and62.3° F. WB temperatures.

TABLE 7 Carbon Footprint Comparison of Traditional Data Center CoolingSystems to the Natural Cycle Energy, Inc. RTDCCS (From example above:2000 KW and 569 tons of cooling). The carbon output per kWh assumed is0.524 pounds per kWh based on Pacific Gas and Electrics publishednumbers. Environmental Impact per kW of Energy Savings TraditionalReduction % Tons Equiv- # of Equiv- # of DC RTDCCS in Carbon Reductionof alent Trees Tons alent Trees Cooling LBs LBs of Foot- in CO2 Mid- toof CO2 Mid to of Carbon Carbon print LBs Carbon Re- Sized Offset/ Re-Sized Off- Released Released Released Footprint duced Cars* YR ducedCars set/YR CRAC Cooled System 7,541,693 1,806,864 (5,734,829) 76.0%2867 434 14,337 1.43 0.22 7.17 CRAH Cooled System- 7,078,642 1,806,864(5,271,778) 74.5% 2636 399 13,179 1.32 0.20 6.59 Chilled Water BasedCRAC Cooled System 6,976,810 1,806,864 (5,169,946) 74.1% 2585 392 12,9251.29 0.20 6.46 w/Containment CRAH Cooled System 6,615,044 1,806,864(4,808,180) 72.7% 2404 364 12,020 1.20 0.18 6.01 w/Containment LiquidCooled 6,181,605 1,806,864 (4,374,741) 70.8% 2187 331 10,937 1.09 0.175.47 Racks Unoptimized Liquid Cooled Racks 4,491,060 1,806,864(2,684,196) 59.8% 1342 203 6,710 0.67 0.10 3.36 Chilled WaterTem-perature Optimized Liquid Cooled Racks 3,638,803 1,806,864 (1,831,939)50.3% 916 139 4,580 0.46 0.07 2.29 Chilled WaterTem- perature Optimizedand Free Cooling Systems Liquid Cooled Racks 3,146,875 1,806,864(1,340,011) 42.6% 670 102 3,350 0.34 0.05 1.68 Chilled WaterTem-perature Optimized and Evaporative Free Cooling Systems Active LiquidCooled 3,054,965 1,806,864 (1,248,101) 40.9% 624 95 3,120 0.31 0.05 1.56Doors, Chilled Water Temperature Optimized and Evaporative Free CoolingSystems Passive Liquid Cooled 2,428,306 1,806,864 (621,442)  25.6% 31147 1,554 0.16 0.02 0.78 Doors, Chilled Water Temperature Optimized andEvaporative Free Cooling Systems Pumped Refrigerant 4,535,449 1,806,864(2,728,585) 60.2% 1364 207 6,821 0.68 0.10 3.41 Systems Air Side3,699,380 1,806,864 (1,892,516) 51.2% 946 143 4,731 0.47 0.07 2.37Economizing *Carbon Calculator (1000 miles driven per month)Environmental Impact per KW of Energy Savings

While particular embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art thatchanges and modifications can be made without departing from theembodiments of this invention in its broader aspects and, therefore, theappended claims are to encompass within their scope all such changes andmodifications as fall within the true, intended, explained, disclose,and understood scope and spirit of this invention's multitudinousembodiments and alternative descriptions.

Additionally, various embodiments have been described above. Forconvenience's sake, combinations of aspects composing inventionembodiments have been listed in such a way that one of ordinary skill inthe art may read them exclusive of each other when they are notnecessarily intended to be exclusive. But a recitation of an aspect forone embodiment is meant to disclose its use in all embodiments in whichthat aspect can be incorporated without undue experimentation. In likemanner, a recitation of an aspect as composing part of an embodiment isa tacit recognition that a supplementary embodiment exists thatspecifically excludes that aspect. All patents, test procedures, andother documents cited in this specification are fully incorporated byreference to the extent that this material is consistent with thisspecification and for all jurisdictions in which such incorporation ispermitted.

Moreover, some embodiments recite ranges. When this is done, it is meantto disclose the ranges as a range, and to disclose each and every pointwithin the range, including end points. For those embodiments thatdisclose a specific value or condition for an aspect, supplementaryembodiments exist that are otherwise identical, but that specificallyexclude the value or the conditions for the aspect.

The invention claimed is:
 1. A system comprising: an initial-stage (IS)cooling assembly that comprises a cooling tower having: an ambient airinlet without an associated heat exchanger, an air outlet, a coolingfluid reservoir disposed proximate a bottom of the IS cooling tower; anda fan dedicated to the IS cooling tower, and configured to move airthrough the IS cooling tower, a final-stage (FS) cooling assembly thatcomprises a cooling tower having: an air inlet, an air outlet, a coolingfluid reservoir disposed proximate a bottom of the FS cooling tower, afan dedicated to the FS cooling tower, and configured to move air firstthrough an FS air-inlet heat exchanger then the FS cooling tower, and avariable flow water pump that is adapted to pump cold water through FSsupply piping; wherein the IS cooling fluid reservoir at least connectsto one or more of the following heat exchangers: the FS air-inlet heatexchanger; and mid-stage (MS) air-inlet heat exchanger for an MS coolingassembly; wherein warmed water returns directly to wet media of the IScooling tower and to the IS cooling fluid reservoir for reuse, whereinthe FS cooling fluid reservoir connects to a cooling coil unit of anindividual server enclosure cooling system and warmed water returnsdirectly to wet media of the FS cooling tower and returns to the FScooling fluid reservoir for reuse, and the individual server enclosurecooling system (ISECS) comprises: a housing; the cooling coil unitmounted in the housing; at least one fan that services the housing; anda computer-based command-and-control system in signal communication withone or more sensors configured to sense at least one cooling parameter,wherein the ISECS connects to a single server enclosure rack.
 2. Thesystem of claim 1 further comprising at least one pump connected betweenthe IS cooling fluid reservoir and the two or more heat exchangers. 3.The system of claim 2 wherein the at least one pump is a variable-speedpump.
 4. The system of claim 3 wherein the ISECS further comprises atleast one additional fan.
 5. The system of claim 4 wherein at least onefan is a variable-speed fan.
 6. The system of claim 5 wherein the ISECSfurther comprises at least one additional cooling coil.
 7. The system ofclaim 6 wherein the computer-based command-and-control system isconfigured to monitor at least one cooling parameter.
 8. The system ofclaim 7 wherein the cooling parameter is air temperature or fan speedand is measured in the server enclosure.
 9. The system of claim 8additionally comprising: the MS cooling assembly that comprises acooling tower having: an air inlet, an air outlet, a cooling fluidreservoir disposed proximate a bottom of the MS cooling tower, a fandedicated to the MS cooling tower, and configured to move air firstthrough the MS air-inlet heat exchanger then the MS cooling tower, aheat exchanger at the air inlet of the MS cooling tower, and a waterpump that is adapted to pump cooling fluid through MS supply piping;wherein the MS cooling fluid reservoir connects at least to one or moreof the following heat exchangers: the FS air-inlet heat exchanger; andan MS air inlet heat exchanger serving the air inlet of another MScooling tower; and wherein warmed water returns directly to wet media ofthe MS cooling tower and to the MS cooling fluid reservoir for reuse.10. The system of claim 9 further comprising at least one variable-speedpump connected between the IS cooling fluid reservoir, the MS coolingfluid reservoir, or the FS cooling fluid reservoir and the two or moreheat exchangers, wherein the ISECS further comprises at least oneadditional fan that is a variable-speed fan; wherein the ISECS furthercomprises at least one additional cooling coil.
 11. The system of claim10 wherein the computer-based command-and-control system adjusts an ISvariable-speed fan, a MS variable-speed fan, or a FS variable-speed fan.12. The system of claim 11 wherein the computer-basedcommand-and-control system adjusts an IS variable-speed pump, a MSvariable-speed pump, or a FS variable-speed pump.
 13. The system ofclaim 12 wherein the computer-based command-and-control system isadapted to adjust fan speed in response to a monitored cooling load. 14.The system of claim 13 wherein the computer-based command-and-controlsystem is adapted to adjust cooling tower pump speed in response tomonitored parameters.
 15. The system of claim 12 wherein thecomputer-based command-and-control system runs software that monitorscooling parameters and optimizes cooling by modifying cooling controls.16. The system of claim 15 wherein the computer-basedcommand-and-control system is adapted to adjust one or more coolingparameters such that the average temperature of air exiting theindividual server enclosure cooling system remains within apredetermined temperature-control tolerance in relation to a set pointtemperature.
 17. The system of claim 16 wherein the computer-basedcommand and control system is a programmable logic controller.
 18. Thesystem of claim 16 wherein the IS cooling fluid reservoir additionallyconnects to a heat exchanger serving a cooling load other than the MS orFS air-inlet heat exchangers.
 19. The system of claim 16 wherein the MScooling fluid reservoir additionally connects to a heat exchangerserving a cooling load other than the MS or FS air-inlet heatexchangers; or the FS cooling fluid reservoir additionally connects to aheat exchanger serving a cooling load other than the ISECS.